Context (decimal.Decimal.Context)

type round =

| Down
(*
Round towards 0; truncate.
*)
| Up
(*
Round away from 0.
*)
| Half_up
(*
Round up if last significant digit is >= 5, else round down.
*)
| Half_down
(*
Round up if last significant digit is > 5, else round down.
*)
| Half_even
(*
Round up if last significant digit is > 5 or next-to-last significant digit is odd, else round down.
*)
| Ceiling
(*
Round up if last significant digit is > 0, else no change.
*)
| Floor
(*
Round down if last significant digit is > 0, else no change.
*)
| Zero_five_up
(*
Round zero or five away from 0.
*)

val string_of_round : round -> string

type t

Controls, precision, rounding, traps (exception handling), etc. settings.

val default : t Stdlib.ref

default is a reference to the default thread-local context.

val make : 
  ?prec:int ->
  ?round:round ->
  ?e_max:int ->
  ?e_min:int ->
  ?capitals:bool ->
  ?clamp:bool ->
  unit ->
  t

make ?prec ?round ?e_max ?e_min ?capitals ?clamp () is a new context value with the given settings and the following traps configured:

conversion_syntax
invalid_operation
div_by_zero
overflow

These may be overridden by using Signal.set (Context.traps context) id bool, or setting a new default context.

val copy : 
  orig:t ->
  ?prec:int ->
  ?round:round ->
  ?e_max:int ->
  ?e_min:int ->
  ?capitals:bool ->
  ?clamp:bool ->
  ?traps:Signal.array ->
  ?flags:Signal.array ->
  unit ->
  t

copy ~orig ?prec ?round ?e_max ?e_min ?capitals ?clamp ?traps ?flags is a deep copy of orig with the given settings. The optional settings default to the same values as those in orig.

val prec : t -> int

val round : t -> round

val e_max : t -> int

val e_min : t -> int

val capitals : t -> bool

val clamp : t -> bool

val traps : t -> Signal.array

traps t is the set of traps for context t. Traps may be set to true or false using Signal.set; a trap set to true raises a runtime exception when its signal is raised. One that's set to false causes the relevant calculation to silently handle the condition and return a result value (typically, NaN).

val flags : t -> Signal.array

flags t is the set of flags for context t. Flags are set to true during a calculation in a context t, when the calculation encounters a condition that triggers the flag. E.g., overflow.

val e_tiny : t -> int

e_tiny t is e_min t - prec t + 1, the minimum allowable exponent of context t.

val e_top : t -> int

e_top t is the maximum exponent of context t.

val pp : Stdlib.Format.formatter -> t -> unit

pp f t pretty-prints the context t.